1. Field of the Invention
The present invention relates to a semiconductor package and a semiconductor package manufacturing method, which are used for electronic equipment and able to improve the heat radiation characteristic of a semiconductor of a large calorific value for a power supply circuit or the like.
2. Description of the Related Art
In recent years, semiconductors are components indispensable for the circuit formation of electronic equipment, and the mounting forms thereof are variously examined and used. In the prior art, there is employed a package form of which the handling and mounting are facilitated, as shown in FIG. 8.
An example of the aforementioned conventional method will be described below with reference to the drawing.
FIG. 8 shows a cross section of the conventional semiconductor package form.
A semiconductor 1 has an upper a-electrode 2 and an upper b-electrode 3 located on one surface and a lower electrode 5 located on the entire other surface. A circuit board 7 has a specified circuit pattern on both of its surfaces. Both the surfaces are connected to each other via through hole conductors (not shown), and one circuit is formed on both the surfaces. Furthermore, to a circuit pattern of the circuit board are sometimes connected balls 8 formed principally of the material of gold, silver, copper, or solder employed as connectors for connection to other electric circuits, thereby facilitating the connection to other electric circuits.
The semiconductor 1 and the circuit board 7 are connected to each other to form a semiconductor package. First of all, the lower electrode 5 is connected to the circuit pattern of the circuit board 7 with solder 6. For the connection of the lower electrode 5 to the circuit pattern, there is occasionally employed a conductive paste or gold in place of the solder 6.
On the other hand, the upper a electrode 2 and the upper b-electrode 3 are connected to the circuit pattern by a wire bonding method generally with a gold wire or an aluminum wire 4.
In this stage, the gold wire or the aluminum wire 4 is, of course, not permitted to come in contact with the portions other than the a-electrode 2 and the b-electrode 3, which are located on the upper side of the semiconductor 1, and a specified distance X must be maintained for the purpose of securing reliability and safety. The distance X is varied depending on the working voltage and current, and therefore, no detail is provided therefor.
Next, in order to protect the circuit constituent portion constructed principally of the semiconductor 1, the semiconductor package is formed with improved protection and handling by covering the surface of the circuit board 7 for mounting the semiconductor 1 so as not to deform the gold wires or aluminum wires 4 used as connectors with an insulating resin 9.
Methods for supplying the insulating resin 9 include a molding method with a die, a method for pouring melted resin, and a method for covering the whole body by placing a powdery or granular resin on the upper surface of the semiconductor 1 and melting the resin by heating.
However, with the above-mentioned construction, the circuit board has a small heat radiation effect when the calorific value of the semiconductor becomes large, or thermal conduction loss occurs even if a circuit board formed of ceramic of good thermal conductivity is employed for the radiation of heat to a heat sink (heat radiation board) or the like. Moreover, the gold wire or aluminum wire has a limit in wire diameter size for wire bonding and is required to be used within the respective allowable current capacities with regard to the wire diameter thereof. Moreover, to cope with a large current, several wires are required to be connected to an electrode located in one place. Furthermore, it is required to secure an inter-electrode distance as the current value increases, and there is an issue that the inter-electrode distance is hard to secure due to variations in wire shape at the time of wire bonding, deformation in the subsequent processing stages, and so on when the gold wire or the aluminum wire is used.
Accordingly, the object of the present invention is to solve the aforementioned issues and provide a semiconductor package and a semiconductor package manufacturing method capable of improving the heat radiation characteristic of a semiconductor of a large calorific value for a power supply circuit or the like.
In order to achieve the aforementioned object, the present invention is constructed as follows.
According to a first aspect of the present invention, there is provided a semiconductor package manufacturing method comprising:
connecting to a heat sink a lower electrode arranged on one surface of both surfaces of a power supply semiconductor that has electrodes on both its surfaces, and connecting a first conductor that has a spherical, convex, or rod-like shape to each of the first electrode and the second electrode arranged on the other surface of both the surfaces of the semiconductor;
forming a first insulating section by covering the semiconductor with a first insulating resin except a connecting portion of the first conductor and a lower surface of the heat sink;
connecting a plate-shaped second conductor to the connecting portion of the first conductor; and
thus manufacturing a semiconductor package.
According to a second aspect of the present invention, there is provided a semiconductor package manufacturing method comprising:
connecting to a heat sink a lower electrode arranged on one surface of both surfaces of a power supply semiconductor that has electrodes on both its surfaces, and connecting a first conductor that has a spherical, convex, or rod-like shape to each of the first electrode and the second electrode arranged on the other surface of both the surfaces of the semiconductor;
connecting a second conductor to a connecting portion of the first conductor;
forming a first insulating section by covering the semiconductor with a first insulating resin except a lower surface of the heat sink and a connecting portion of the second conductor; and
thus manufacturing a semiconductor package.
According to a third aspect of the present invention, there is provided a semiconductor package manufacturing method comprising:
connecting to a heat sink a lower electrode arranged on one surface of both surfaces of a power supply semiconductor that has electrodes on both its surfaces, and connecting a first conductor that has a spherical, convex, or rod-like shape to each of the first electrode and the second electrode arranged on the other surface of both the surfaces of the semiconductor;
connecting a plate-shaped second conductor to a connecting portion of the first conductor;
forming an insulating section by covering whole body with an insulating resin, and thereafter removing the insulating resin of a lower surface of the heat sink and a connecting portion of the second conductor; and
thus manufacturing a semiconductor package.
According to a fourth aspect of the present invention, there is provided a semiconductor package manufacturing method as defined in any one of the first to third aspects, wherein the first conductor has a stepped shape and includes a small-diameter portion to be fit in a hole of the second conductor, a large-diameter portion that is thicker than the small-diameter portion and able to be engaged with a periphery of the hole of the second conductor, and a stepped portion arranged at a boundary between the small-diameter portion and the large-diameter portion, and the second conductor is connected to the connecting portion of the first conductor by engaging the periphery of the hole of the second conductor with the large-diameter portion while fitting the small-diameter portion that serves as the connecting portion of the first conductor into the hole of the second conductor.
According to a fifth aspect of the present invention, there is provided a semiconductor package manufacturing method as defined in any one of the first to third aspects, wherein the first conductor is connected to the second conductor in a state in which a lower surface of the second conductor pushes against and comes into contact with an upper end surface of the first conductor.
According to a sixth aspect of the present invention, there is provided a semiconductor package manufacturing method as defined in any one of the first to fifth aspects, wherein the first conductor has an uneven portion on its side surface, and the first insulating resin twines around the uneven portion of the side surface of the first conductor.
According to a seventh aspect of the present invention, there is provided a semiconductor package manufacturing method as defined in any one of the first to sixth aspects, wherein the insulating resin has great thermal conductivity.
According to an eighth aspect of the present invention, there is provided a semiconductor package manufacturing method as defined in any one of the first to seventh aspects, wherein the second conductor is covered with an insulative coating film made of a thermoplastic insulating resin, and the insulative coating film is removed or pushed aside by an effect of any one of heat, pressure, and vibration or a combination of these factors when connecting the second conductor to the first conductor, by which the second conductor and the first conductor are brought in contact and connected with each other.
According to a ninth aspect of the present invention, there is provided a semiconductor package manufacturing method as defined in any one of the first to eighth aspects, wherein a plurality of first conductors are connected to one electrode of the semiconductor.
According to a 10th aspect of the present invention, there is provided a semiconductor package manufacturing method as defined in any one of the first to ninth aspects, wherein the second conductor has at its one end a bent portion or an extruded protruding portion, the bent portion or the extruded protruding portion located at the one end of the second conductor is employed as the first conductor to be connected to the electrode of the semiconductor and the connection of the first conductor to the second conductor is eliminated.
According to an 11th aspect of the present invention, there is provided a semiconductor package manufacturing method as defined in any one of the first to 10th aspects, wherein the connecting portion that belongs to the first conductor and is connected to the second conductor is a tip portion of the first conductor.
According to a 12th aspect of the present invention, there is provided a semiconductor package manufactured by the semiconductor package manufacturing method defined in any one of the first to 11th aspects.
According to a 13th aspect of the present invention, there is provided a semiconductor package comprising:
a power supply semiconductor having electrodes on both its surface;
a heat sink connected to a lower electrode arranged on one surface of both the surfaces of the semiconductor;
a first conductor that has a spherical, convex, or rod-like shape and is connected to each of the first electrode and the second electrode arranged on the other surface of both the surfaces of the semiconductor;
a first insulating section of a first insulating resin for covering the semiconductor except a connecting portion of the first conductor and a lower surface of the heat sink; and
a plate-shaped second conductor connected to the connecting portion of the first conductor.
According to a 14th aspect of the present invention, there is provided a semiconductor package comprising:
a power supply semiconductor having electrodes on both its surface;
a heat sink connected to a lower electrode arranged on one surface of both the surfaces of the semiconductor;
a first conductor that has a spherical, convex, or rod-like shape and is connected to each of the first electrode and the second electrode arranged on the other surface of both the surfaces of the semiconductor;
a plate-shaped second conductor connected to a connecting portion of the first conductor; and
an insulating section for covering the semiconductor, the heat sink, the first conductor, and the second conductor with an insulating resin except a lower surface of the heat sink and a connecting portion of the second conductor.
According to a 15th aspect of the present invention, there is provided a semiconductor package as defined in the 13th or 14th aspect, wherein the first conductor has a stepped shape and includes a small-diameter portion to be fit in a hole of the second conductor, a large-diameter portion that is thicker than the small-diameter portion and able to be engaged with a periphery of the hole of the second conductor, and a stepped portion arranged at a boundary between the small-diameter portion and the large-diameter portion, and the second conductor is connected to the connecting portion of the first conductor by engaging the periphery of the hole of the second conductor with the large-diameter portion while fitting the small-diameter portion that serves as the connecting portion of the first conductor into the hole of the second conductor.
According to a 16th aspect of the present invention, there is provided a semiconductor package as defined in any one of the 13th to 15th aspects, wherein the first conductor is connected to the second conductor in a state in which a lower surface of the second conductor pushes against and comes into contact with an upper end surface of the first conductor.
According to a 17th aspect of the present invention, there is provided a semiconductor package as defined in any one of the 13th to 16th aspects, wherein the first conductor has an uneven portion on its side surface, and the first insulating resin twines around the uneven portion of the side surface of the first conductor.
According to an 18th aspect of the present invention, there is provided a semiconductor package as defined in any one of the 13th to 17th aspects, wherein the insulating resin has great thermal conductivity.
According to a 19th aspect of the present invention, there is provided a semiconductor package as defined in any one of the 13th to 18th aspects, wherein the second conductor is covered with an insulative coating film made of a thermoplastic insulating resin, and the insulative coating film is removed or pushed aside by an effect of any one of heat, pressure, and vibration or a combination of these factors when connecting the second conductor to the first conductor, by which the second conductor and the first conductor are brought in contact and connected with each other.
According to a 20th aspect of the present invention, there is provided a semiconductor package as defined in any one of the 13th to 19th aspects, wherein a plurality of first conductors are connected to one electrode of the semiconductor.
According to a 21st aspect of the present invention, there is provided a semiconductor package as defined in any one of the 13th to 20th aspects, wherein the second conductor has at its one end a bent portion or an extruded protruding portion, the bent portion or the extruded protruding portion located at the one end of the second conductor is employed as the first conductor to be connected to the electrode of the semiconductor and the connection of the first conductor to the second conductor is eliminated.
According to a 22nd aspect of the present invention, there is provided a semiconductor package as defined in any one of the 13th to 21st aspects, wherein the connecting portion that belongs to the first conductor and is connected to the second conductor is a tip portion of the first conductor.
The present invention is to connect the lower electrode of the semiconductor to the heat sink, directly conduct the radiated heat to the heat sink, and form the conductor of a copper plate in place of a gold wire or an aluminum wire. Moreover, by connecting the first electrode and the second electrode of the semiconductor to the conductor using a rod-shaped electrode thicker than a gold wire or an aluminum wire, there is provided a semiconductor package that is able to cope with a large current value and easy to secure a distance between the conductor and the semiconductor, giving solution to the aforementioned issues.